Van der Sar spent six years at Manchester United, during which time he won four Premier Leagues and a Champions League.
He made 186 appearances for the club and played alongside some of the biggest names in United's modern history.
The Dutchman feels that the current United side are a far cry from the glory days he played through.
"Of course it's difficult. I left there eight years ago and it was a tremendous last six years of my career, winning four Premier League titles and playing in three Champions League finals," he told ESPN FC.
"So it's a long way from the position where they are in now.
"And of course they have changed managers a couple times now and the real progress is not seen yet, only the thing that they bought in the summer.
"They bought younger, inexperienced players with a certain desire and hunger, and not like the big names they bought the last six, seven years."
Van der Sar now operates as Ajax's CEO, after being promoted from marketing manager in 2016.
His memories of Old Trafford consist of a dressing room full of loud voices, something that he feels has been lost in Ole Gunnar Solskjaer's current crop.
"I think for ourselves, when I came in the dressing room we had Ryan Giggs, you had [Paul] Scholes, you had [Rio] Ferdinand, [Gary] Neville and even Roy Keane at that time," he said.
"So I think there's always been strong characters. And I think for the last couple of years the strong characters have disappeared and [are] not making a difference anymore."
Despite losing their bite, Van der Sar believes United have the reputation and resources to recover and return to the summit of English football once more.
"Of course, the name is there. And of course the following they have all over the world," he said.
"But for a player... you want to play at a certain level, you also want to have an idea that you can win trophies.
"They must take that opportunity to improve the squad and make the world-class players they have – or the players that they're going to sign – feel welcome and that there's a good path to where they're going to go to."
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